[Groff] Several file arguments to groff

[Bernd Warken]

`groff', `troff', `grog', and `groffer' allow to use several different
file arguments.  So far, only file names with the same macro package
are really supported.

If the file arguments use different macro packages, groff usually
generates many errors.  For example, try

  groff -man man/groff.man -me doc/meintro.me -ms doc/pic.ms -Tlatin1

in groff's top source directory.  This produces many wrong macro
usages and error reports, being just a bit different if the sequence
of the arguments is changed.

This bad concept should be either fixed or documented in the
corresponding man pages and the info file.  Fixing is easy for `grog',
quite hard for `groff', maybe unnecessary for `troff'.  If it is not
fixed, but only documented, `groffer' needs a major update.

Bernd Warken <address@hidden>